The brain is a highly vascularized organ and any surgical procedure performed in it inevitably disrupts its delicate vasculature;addressing bleeding during brain surgery is of utmost importance, as excessive bleeding within the confined space of the skull can quickly lead to serious debilitating complications and death. Conventional techniques for bleeding control have very limited utility for the brain. The standard for bleeding control during brain surgery has practically not changed for many decades, with oxidized cellulose, gelatin and collagen as the commonly used materials;thrombin is often deployed in conjunction with these materials to hasten hemostasis. Collectively, the main issues associate with these approaches are, (i) require preparation, (ii) non-conformal and non-adhesive to the site of application, (iii) lack transparency and thus limited capacity for visualizing the status of hemostasis, (iv) material of blood/mammalian origin and thus the risk of disease transmission, and (v) swelling. In this project, we will formulate a transparent, biocompatible/biodegradable and formable/conformable/adhesive hemostatic agent aiming for controlling the bleeding during brain surgery. In parallel, we will validate the lack of cytotoxicity potential of the hemostatic agent;this will be followed by in vivo biocompatibility testing. The in vivo efficacy validation study will be performed in rat brain surgery model. PUBLIC HEALTH RELEVANCE: Over 130,000 neurosurgical procedures are performed on the brain in the US each year. The brain is rich in delicate blood vessels and any surgical procedure performed in it inevitably disrupts the structure. Addressing bleeding during brain surgery is of utmost importance, as excessive bleeding within the brain can quickly lead to serious debilitating complications and death. Due to the small size of the vessels and the delicacy of the tissue, typical techniques such as ligature and electrocautery commonly utilized for controlling bleeding vessels in various surgical procedures have very limited applicability in the brain. The standard for bleeding control during brain surgery has practically not changed for many decades;many of the surgical adjuncts currently being utilized to control bleeding are not optimized for brain surgery and many of these products are blood or mammalian derived, which carry the risk of disease transmission. The goal of this project is to develop a non-blood, non-mammalian and natural material based hemostatic agent optimized for controlling bleeding during brain surgery.